Water is air. Lava is air. Obsidian cannot be made.
World generation stops producing fluid. Oceans, rivers, lakes, aquifers and springs come out dry — and their basins stay carved. Lava goes the same way: lakes, springs, the deep lava under the caves, the basalt deltas, and the Nether's lava sea.
The only obsidian left in the Overworld is what the world already holds: the frames of its ruined portals, and the odd lucky chest. Each ruin still gives up about four real blocks.
Nothing is added to the game. Every rule is vanilla; the mod only takes away.
Without its lava sea the Nether loses its main source of light, and the sea becomes a vast open floor.
drain_lava=false keeps a dry Overworld without the obsidian lock, for packs that want the landscape but not the progression change.config/drained.properties — every rule has its own switch: water, lava, bare sea floors, crying portals and the share of real obsidian they keep, and dry monuments. Chest loot is vanilla by default; one more switch strips obsidian from chests for a harder lock.
Enjoying the mod? Buy me a coffee on Ko-fi** Source : https://github.com/BackupBackupFede/bulk-trade